Tag Archive for chocolate

Just a relatively quick post, as things are have been and are continuing to insist upon being busy – I’ve had a round of assessment for my PhD (my mid-candidature review), participated in a speaking competition about my PhD, done a talk about “seducing with neuroscience” (maybe I’ll post something about that at some stage – it’s not food-related but it is very interesting, and despite the evocative name it’s actually about how neuroscience information influences people’s judgments about the credibility of explanations), and now I’m madly analysing data to get an abstract submitted for a conference in November prior to leaving for a conference coming up in September (yep, it’s overseas-trip-time for me again, for the fourth time in 18 months – more on that later too, I guess).

SO! Another one to file away in the “how to influence people’s perception of food” category – can you influence people’s perception of food by manipulating something as simple as the weight of the dish it’s served in?

YES! It seems…

In a study by Piqueras-Fiszma and colleagues, participants were asked to rate 3 yoghurt samples in terms of flavour intensity, density, price expectation and liking. The yoghurt samples were served in three bowls that were all identical except for their weight: they were white ceramic bowls to which a hidden weight could be attached, so that the lightest bowl was 375g, the intermediate-weight bowl was 675g, and the heaviest bowl was 975g. Each bowl was used to serve a 150g sample of plain old Greek yoghurt (important information for study replication: it was purchased from Tesco!).

Participants had to hold the bowl in one hand while they sampled the yoghurt, and each bowl was taken away before the next one was given, so that there was never a chance to directly compare the weights.

Of course, it was the exact same yoghurt in each of the three samples that each participant tried – the only difference was the weight of the bowl the yoghurt was served in. But the participants didn’t know that. They probably assumed they were taste-testing different yoghurts.

Results showed that the heavier the bowl, the higher people rated the perceived density of the yoghurt when they sampled it, and the more money they expected to pay for it. Also, the heavier the bowl, the more participants liked the yoghurt. Perceived flavour intensity was not significantly affected by the weight of the bowls.

So everyone go out immediately and buy really heavy bowls and plates! Serve your things in heavy dishes all the time! Force your dinner guests to hold the crockery in their hands as they eat! Make people think your food is more fancy, more expensive, more lovely!

Or not. These results probably can’t be generalised too much – maybe you only get this effect for particular foods, and yoghurt just happens to be one of them. Maybe the effect changes depending on other properties of the food, e.g. maybe the volume of yoghurt is difficult to visually gauge because it’s just a big amorphous lump, so people’s perceptions are only influenced when the amount of food is difficult to get an idea of. Maybe putting something a bit more discrete, like an apple, into the different bowls would get a different result.

And it would be interesting to do a study investigating whether the weight of the vessel influences the amount of food eaten – maybe if the bowl is heavier, the food seems denser, and perhaps the brain is tricked into thinking the food is more calorific and so satiety occurs sooner. Who knows? I mean, there are many cues that the brain uses to determine satiety, so maybe it would be difficult to detect an effect of serving dish weight, but it is intriguing…

Anyway, it’s brownie time. Or blondie, as the case may be, I don’t know what defines one versus the other. Do blondies simply lack the predominance of cocoa or milk/dark chocolate in the batter? Anyway, the photos above are of some ridiculously delicious blondies (we’ll go with blondies for the name), featuring one of the greatest things known to humankind: peanut butter. They are peanut butter and waffle blondies (they have waffle crumbs throughout them) with dark chocolate chips. I recently made a variation of the recipe, photos of which are below: peanut butter, waffle and malt biscuit blondies with white chocolate chips and strawberries. I made those for a friend who recently endured an incredibly difficult experience (understatement of the century) and has just gotten out of hospital.

Here’s a pint of Guinness. Now, slán go fóill, y’all, because I’m off to Ireland!

Well, not immediately. (And why yes, I did bake a cylindrical Guinness chocolate cake and carve it into the shape of a pint glass and top it with Guinness foam. Because Guinness cake has been done a million times before so it was time to take it up another notch. BAM!)

But I leave in a bit under two weeks to go and work with collaborators in Dublin for a couple of weeks to analyse the data I’ve been collecting over the past 16 months. Could I have even hoped for better-located collaborators? I think not. After that, my boyfriend Chris and I will be hanging around in Ireland for a few extra days before hopping over to London and taking in as much of the UK as we can over the course of several weeks.

So, any suggestions for particular places we should go? Seriously, anywhere in Ireland or the UK is up for consideration, especially if there is food involved. Leave a comment or e-mail me with suggestions, as they will be greatly appreciated.

Also, since we’ll probably be, you know, hopefully, sort of, kind of busy, it means that once I leave I probably won’t be updating the blog very much until I’m back next year. I’ll do what I can, but alas – I can’t make any promises. I won’t be blogging about my travels since I think of this as more of a food/science blog than a personal blog (if I do come across anything particularly amazing in terms of food and/or science, I’ll certainly try to post it).

However, if you want to follow along with my travels, leave a comment or send me an e-mail to let me know and then when I start uploading photos to the online photo album I use, I’ll send you the link. Last time I was overseas, in April this year, I was pretty good at uploading photos every day.

Go get a nice little spoonful of the bitter compound 6-n-propylthiouracil. Taste it. Can’t taste it? Ok, listen to me — never become a writer. Nip that in the bud right now.

Or at least never write about dairy products. Just… do us all a favour and… don’t. The world doesn’t need your rigid, prosaic descriptions of dairy products.

Maybe you’re one of those rare people who doesn’t have 6-n-propylthiouracil in their household or workplace chemical cupboard. If so, go to the fridge. Get out the cream cheese. (Don’t you dare tell me you don’t have 6-n-propylthiouracil or cream cheese. That is unfathomable and disturbing.) Eat a little piece of it and think carefully. Now, write a description of it. What’s important to you about it? What does it look like? What tastes and flavours can you pick up? What’s the texture like? Write it down on a piece of paper, hand it to me, and I’ll read it and shake my head disapprovingly if you’ve said anything as naff as “sweet”, “sour” or “milky”. Such an unimaginative and uninspired attempt at imagery… it could only have been done by a person whose pretty poor at tasting 6-n-propylthiouracil. Shame on you.

As I mentioned in the previous post, the different levels of sensitivity people have to bitter tastes can be associated with different behaviours. People who have greater sensitivity to bitter chemicals such as phenylthiocarbamine and 6-n-propylthiouracil (PROP) may perceive food differently, perhaps finding bitter foods less palatable (depending on the bitter compounds in the food, the intensity of the bitterness, and so on), which is a bit of a worry if the bitter foods are also healthy ones. However, it looks like the gene variant combination that bitter tasters have compared to non-tasters might also be associated with other differences in food perception. Fat content seems to be one of those, with research finding that people who are good at tasting bitterness also seem to be pretty good at discerning fat content and creaminess in foods. And they’re better at describing these things too. (And our fingers continue to hover over the button to purchase bitter taste phenotype kits so we can finally figure out how all of this stuff applies to us…)

Participants in a study by Kirkmeyer and Tepper evaluated various dairy products (such as cream cheese, condensed milk, sour cream, milk, ice-cream and yoghurt) and described each of the products in terms of appearance, taste/flavour and texture. A rather interesting pattern became evident once the participants were sorted according to their gene variant combination (genotype) for tasting the bitterness of PROP.

Non-tasters used very simple terms and a limited vocabulary — products were described in terms of being sour or sweet or milky; all the more basic and obvious descriptors for something like a dairy product. PROP tasters, however, used a much more varied lexicon, favouring descriptors such as “rich, buttery, creamy, light, grainy, gritty and sandy” in their evaluations. When comparing the descriptors in terms of whether they describe the sweet-sour dimension of the products taste or its flavour-texture dimension, it became apparent that tasters tended to place more emphasis on the flavour-texture dimension rather than the sweet-sour dimension, whereas non-tasters gave flavour-texture and sweet-sour equal importance.

This tells us that maybe bitter tasters judge creaminess and fat content using different cues to non-tasters, more related to the texture and the sensation of the food in the mouth. A few studies have found that tasters (or at least supertasters) are better at judging the fat content or creaminess of a liquid dairy product than non-tasters, so if they are using different cues, then they’re possibly the more accurate ones to use. But why are people who are good at tasting a particular bitter chemical better at judging texture?

Maybe the papillae, the tiny little lumpy structures on the tongue, some of which harbour taste-buds. PROP supertasters tend to have a greater density of tongue papillae, allowing perhaps for a more sensitive and nuanced perception of whatever’s on the tongue. So somehow, maybe the PROP gene is associated with the gene/s for papillae formation and expression.

The upshot of all of this is that it could be interpreted from a health perspective. Some research results suggest that not only are PROP tasters better at judging the fat content and creaminess of food, but that they also have a preference for the higher-fat, creamier food because, well, they can tell the difference. Give them low-fat ice-cream and they can tell it’s not as enjoyable to their energy-craving brain as full-fat ice-cream, but give the low-fat ice-cream to non-tasters and maybe they don’t care so much. Is this genuinely the case? And if so, does it affect long-term food intake and healthiness? Unfortunately, not much research has looked at whether these potential health concerns are, well, actual health concerns that we should be concerned about. All in good time, though.

In the meantime, PROP non-tasters: not the best dairy product reviewers.

In the mood for dairy, then? There’s plenty of cream on these chinotto black forest cupcakes. Yep, chinotto. This is, like, the flavour combination of the year for me. I don’t even like chinotto that much by itself, but paired with chocolate, it could not be more flawless. A cursory Google search reveals no other mentions of the chinotto-chocolate — CHINOCOLATE, if you will — combination, but maybe I can start a trend. You will try it, yes?

And you don’t have to go with my elaborate Russian Constructivism-inspired cake decoration if you really don’t want to. I don’t have the time to hunt you down if you don’t do it.

Read on for the recipe for chinotto black forest cupcakes with whipped cream and chocolate cherry truffles.

You might remember my previous attempt at making hot ice-cream — the ice cream that you poach in hot water and then it melts as it cools to room temperature. It worked, technically, but I wasn’t happy with the flavour since it just tasted like cream cheese, which, you know, doesn’t taste like ice-cream (unless you have cream cheese ice-cream, I guess, but who has that? That’s right, no one. Well, some people, but they’re not the sort of people I want anything to do with).

So I went on the quest to develop a hot ice-cream recipe that tastes like normal vanilla icecream. And after some experimentation and various mishaps, ye gods, I think I’ve actually done it.

Jack at Homologous Legs happened to tweet about the old recipe at one stage, saying that he’d be all for it if the hot ice-cream was in iced chocolate, as opposed to the iced coffee I’d put it in to make the reverse affogato. And I thought yes, that’s a good point. So in this iteration of the recipe, I changed the lovely bath in which the hot ice-cream resides from iced coffee to a cinnamon chocolate frappé. Just because I can. (But methylcellulose also thickens at low temperatures as well as 50°C+ temperatures, so the frappé is going to cause the ice-cream to melt and then solidify again, which I pretend is all part of the thrilling and dynamic dining experience.)

So there you go. Hot ice-cream that melts as it cools. It’s kind of amazing and it defies the senses.

You know else is kind of amazing and defies the senses? (Behold the world’s most stunning segue.)

Synaesthesia.

For those of you who have the unfortunate circumstances of not knowing about the mind-melting amazingness of synaesthesia, it is a condition in which perception of a stimulus in one modality is experienced in an additional modality. What does that mean?

Well, imagine that every time you heard a dog bark, your visual perception was spontaneously and involuntarily tinged with purple.

Or imagine that as you read this blog, you’re visually experiencing a relentless cavalcade of colours with each different letter you look at.

That happens to synaesthetes — they experience a vivid and completely involuntary cross-over between senses (and possibly cognitive systems). And there are different kinds of synaesthesia involving cross-over between different senses and cognitive processes such as language processing. Grapheme-colour synaesthesia is the one where people experience a colour in association with different letters or numbers (e.g. the letter A conjures up the perception of red or is perceived as being inherently red). Sound-colour synaesthesia is the one where hearing a particular noise or even a particular note on a musical instrument causes the synaesthete to experience a particular colour. And studies have shown that these particular associations (such as A = red or dog barking = purple) generally remain steady over the synaesthete’s lifetime. So play a B-flat on a cello for a synaesthete and perhaps they see orange, then come back 25 years later and play that B-flat on a cello again and ask them what colour they experience — it’ll be orange.

But within the scope of the neuroscience of taste perception, one type of synaesthesia is just lobe-explodingly interesting: lexical-gustatory synaesthesia. When people with this synaesthesia hear or read or even think a particular word, they consequently experience a particular taste. Not just that, but words conjure up the sensation of taste and temperature and texture in the mouth (perhaps not surprising to those of you who remember when I discussed the primary taste cortex in this post and mentioned that some neurons in the primary taste cortex fire preferentially to particular food temperatures and textures as well as tastes).

It’s estimated that less than 0.2% of the population experiences this lexical-gustatory synaesthesia, so it’s pretty uncommon and it’s difficult to research when there are so few potential research participants (damn it, I find it hard to get research participants and all I need are right-handed males aged 18-40). But here are some of the word-taste associations that lexical-gustatory synaesthetes experience, according to the literature…

“for synaesthete JIW, the word jail floods the mouth with the taste of bacon”

“for SKM, the word dean evokes the precise and consistent notion of minced beef in gravy”

“for synaesthete JG for example, the name Adrian tastes of lettuce coated with Caesar salad dressing, and for CS, part tastes of chicken noodle soup”

“for JIW, the words message, college and edge all taste of pork-pie/sausage meat”

Pretty specific, huh? And kind of, well, unpleasant in some cases. I’m in no hurry to taste congealing pot-roast gravy, never mind have it forced upon me by my brain every time I read Nancy Drew (I’ve never read Nancy Drew, but what if I wanted to? What if I wanted to?!).

You might have guessed from those little excerpts the direction in which lexical-gustatory synaesthesia research has headed — what are the specifics of a word that mean it’s associated with a taste? Are there generalisable trends within each synaesthete, e.g. do words that sound the same generate similar tastes? And what about made-up words — do they generate a taste? And if they do, why? More, tell me more!

Well, to start with, one thing is pretty straight forward — if something has a taste, the word for that something will generally taste like that something. So the word asparagus conjures up the taste of asparagus. It might be the taste of over-cooked asparagus for one synaesthete and raw asparagus with freshly ground pepper for another, but generally there is a pretty blatant link between food words and their respective food tastes.

Another of the most clear-cut findings is that sometimes there are obvious associations between parts of words and the name of what they taste like. For example, “cinema tastes of ‘cinnamon rolls’ (JG), Jackson tastes of ‘Cracker Jacks’ (both MZ and CS), village tastes of ‘vanilla slice’ (SKM), and dogma tastes of ‘hotdogs’ (DMS).” So there’s some sort of word-association going on here based on key sounds and letter groups within a word.

It also seems like particular sounds within words might be the point that the taste association clings to. That’s why message, college and edge taste of sausage meat (the /dzj/ sound in all of them and in sausage) and things with a /k/ sound taste of egg yolk to JIW.

This all kind of makes sense, but what would you predict would happen with made-up words, non-words? These do generate tastes in the synaesthete, even if the synaesthete has never encountered them before. It looks like non-words associate with a taste based on how similar they are to real words. For example, if presented with the non-word keach, a lexical-gustatory synaesthete might experience the taste that’s usually associated with beach or teach. Even non-synaesthetes can see the similarity between those words, but synaesthetes might have a broadened sense of word similarity, in that a word like spluk results in the taste that’s usually associated with luck, even though spluk and luck are technically very different words.

Despite there being very few individuals with lexical-gustatory synaesthesia to study, there are a few papers out there on the topic that suggest some very interesting theoretical underpinnings for this type of synaesthesia, and some incredibly nifty experiments have gone down. I will, however, go into that another time (well, in my next post).

In the mean time, just reflect on the fact that you are not currently tasting lumpy gravy or cold potato skins or oily salad dressing while reading this. If you were anything like the synaesthete JIW, you would be experiencing tastes in response to 56% of words from your own speech, the speech of others, inner speech and reading. An almost constant parade of tastes…

Personally, my strategy would be that I’d memorise a list of all the words that don’t generate a taste, then try to speak and think exclusively in those words, just for a little respite. Think of it as being like that guy who wrote a story that didn’t contain the letter E. So… difficult… I think… hi… how do you do today… do you… want to… stuff into your mouth… hot rich dairy product? Look down for… instructions…

Read on for the recipe for hot vanilla ice-cream in cinnamon chocolate frappé.

These yuzu chocolate mud cakes with fizzy yuzu icing may be my favourite thing I’ve baked in a long time. The texture of the cakes is ridiculous (it’s kind of like peanut butter, in that it sticks to the roof of your mouth in a delightfully and irritatingly luxurious way). And yuzu, well, I currently pay $40 for a 300ml bottle of yuzu juice (weep!) but I’ve just tracked down Australia’s only yuzu grower, who just happens to be about a 2-hour drive south from here, so if I had a car I would probably be there right now (and possibly passed out amongst the rinds of the dozens of yuzu fruit I had gorged on) but I’ll have to wait a little longer until I can beg/borrow/win a car. Then… everything I cook will have yuzu in it.

Ev-er-y-thing.

Alright, so. Enough yuzu, more science.

Eating food is a multisensory experience. (Hurr durr derp derp that’s pretty obvious.) It’s all pretty damn important when it comes to the perception of food and the enjoyment of eating: the look, the smell, the taste, the texture. But who’s the lonely sense who’s been left out of the party? It’s hearing! Poor, neglected hearing. He wants to come to the party too. He wants to consort with the other senses with reckless abandon. Why won’t you let him? Why won’t you letttt himmmm?

We might not think much about hearing’s contribution to food (beyond the pleasing crunch of crunchy things — more on that in a future post) but it turns out that the brain doesn’t exclude hearing from the party completely. In fact, our brains make implicit associations between tastes and sounds. We might not be aware of them on a conscious level (is a sweet taste high-pitched or low-pitched?) but with the right sort of task, as provided by experimental psychology, we can get a look at the furtive, illicit dalliance between hearing and taste. How thrilling.

So the task is like this. You sit at a computer with your hands on the keyboard. Words are going to flash up one after another on the screen, and they’ll either be sweet words (words like sugar, honey, maple syrup) or salty words (words like salt, crisps, pretzel). Sometimes you’ll also hear sounds played over some headphones (2 seconds of sound played on an instrument such as a violin, piano or bassoon). The sounds will either be high-pitched or low-pitched. You and some other participants start off the experiment on Condition 1, then change to Condition 2 (while other participants will start on 2 and change to 1).

Condition 1
Press the A key if: you see a sweet word or hear a high-pitched tone.
Press the L key if: you see a salty word or hear a low-pitched tone.

Condition 2
Press the A key if: you see a sweet word or hear a low-pitched tone.
Press the L key if: you see a salty word or hear a high-pitched tone.

You as a participant probably won’t notice anything amazing during the experiment. But when the researchers look at your reaction times (i.e. how fast you were at pressing the correct key after you saw a word or heard a sound) they’ll notice something very interesting. You responded significantly faster in Condition 1 than in Condition 2.

For some reason, you’re faster when a sweet word and a high-pitched tone are associated (Condition 1) than when a sweet word and a low-pitched tone are associated (Condition 2). Likewise, you’re faster when a salty word and a low-pitched tone are associated (Condition 1) than when a salty word and a high-pitched tone are associated (Condition 2). Somehow, the sweet-high and salty-low combinations just make more sense to your brain, enabling you to react and identify them more quickly — and more accurately, since participants made fewer errors in Condition 1 (although the error rates in Condition 1 and 2 weren’t significantly different statistically).

Another study using the same kind of experiment found a significant association between sour words and high-pitched sounds, and between bitter words and low-pitched sounds. However, these researchers have also tested sweet, sour, salty and bitter altogether using a different task, and the pitch associations for salty and bitter disappeared, although the associations between sour words and high-pitched sounds and between sweet words and high-pitched sounds were still there. Hmm.

And it seems like we don’t really have a good explanation for why the brain does this. There are plenty of ways of drawing parallels between properties in different senses — for example, when comparing hearing to vision, the loudness of a sound might be thought of as the equivalent of the brightness of a colour, since increased loudness and increased brightness are both experienced by us as being more “intense”. So maybe we just don’t have a good enough grasp of the properties of taste to be able to figure out something like why sweet is somehow a parallel for high-pitched. Is there a biological basis to the association? Or is it cultural somehow? Do people from different cultures experience the same associations? Would the results be any different if actual tastes were used (e.g. a bit of sugar on the tongue) instead of taste-related words?

And… and… can we influence the perception of taste by using sound? If the basis of the association is biological, maybe closely connected or overlapping brain regions are responsible for sweet tastes and high pitches. There certainly is overlap between the hearing and taste sensory pathways, not just at later stages of cortical processing but in the early stages too, as the primary taste cortex (which I discussed in my previous post) is located partly in the insula, which also plays a pretty big role in auditory processing (Bamiou et al. 2003).

So it’s a big and tenuous jump, but… can we influence the perception of taste by using sound? If the association is due to neuronal connectivity, would something taste sweeter if we played high-pitched music compared to low-pitched music? Or would something just taste wrong somehow if sound that wasn’t associated with it was played? Intriguing possibilities…